Hi Dana,
I would try bidding thru Priceline. I have been doing this for the last 3 trips to Disney. We always spend the majority of our vacation on Disney property, but spend a few extra days beforehand doing other things like universal and SeaWorld.
Your odds usually improve on Priceline the closer you get. I picked up the Wyndham Resort, right across the street from Downtown Disney for 2 nights at $62 per night. This hotel usually goes $150-200 per night.
With Priceline, you are not guarenteed a particular hotel, but you can guarentee a general area (Disneyworld and vicinity) and a quality level. My last 3 trips we have gotten the Wyndham twice and the Hilton once.
If you bid on priceline, and ask for a Resort hotel, you will generally get either the Wyndham or the Hilton, both at DTD. Other hotels that have come up are the Swan and Dolphin, although this is rare. The Mariott Orlando World Center has also been known to come up.
In my opinion, very little risk, and you are pretty much guaranteed a great price on a great hotel.
If you want more info, let me know.
Steve